Guardiola's appointment, announced in January, has created considerable hype in Germany, amid hopes that the man who took Barcelona to 14 titles in four seasons will bring glamour to the Bundesliga.
"At the top clubs, you are always under pressure but I believe in myself and I accept this challenge without a problem," the 42-year-old said in German, which he has been studying for the last six months.
"I will, of course, make changes, but I want to keep the level that Bayern has already achieved."
Guardiola has his work cut out to match last season's achievements when Bayern won the treble of European, cup and league titles, plus the pre-season German Super Cup, under predecessor Jupp Heynckes.
Having only flown into Munich with his family on Sunday night after his year-long sabbatical in New York, Guardiola spoke mainly German during the hour-long press conference but also broke into Spanish, English and Italian.
"I have lived for the last year in New York and it's not the optimal place to learn German but it's a gift, a joy to be here," he said.
"The decision to come to the club was based on its history and its players.
"It's a fresh challenge for me, my time in Barcelona was wonderful, but I needed a new challenge.
"Bayern Munich gave me the opportunity, I am prepared to give my best. I'm ready."
Guardiola, whose first training session takes place on Wednesday evening, repeatedly stressed that he needed time to get comfortable with the new language, his new home and his new team.
He admitted that he was nervous as he faced about 300 reporters but was relaxed enough to crack a few jokes.
"Perhaps my family should move in with me at Säbener Strasse [Bayern's training ground], because I'll be living there for the next six months," he said.
He also joked that while he had watched all of Bayern's games last season at his New York apartment, he had not been allowed to come to Germany any earlier "because my German teacher is a Borussia Dortmund fan".
Guardiola, however, called for calm amid high expectations for the Bavarian giants.
"Give me a bit of time, step by step, my German isn't good enough, but I'll try to reach a high level," he said.
"If a side has won four titles, the need for a high number of changes isn't great."
Bayern chairman Karl-Heinz Rummenigge meanwhile revealed that Germany striker Mario Gomez would be training with the team on Wednesday, despite rumours of an imminent transfer to Italy.
"I can confirm Gomez will be training with us in Wednesday, I have read the rumours, but there have been no concrete offers from Italy," said the Bayern boss.